The present invention relates to an electromagnetic relay switch assembly.
Various types of electromagnetic relay switch assemblies are currently commercially available. In general, the prior art electromagnetic relay assemblies comprises an electromagnet unit including an electromagnetic coil means, a movable plate member of a magnetizable material supported for pivotal movement between attracted and released positions, a ratchet wheel and means for stepwisely rotating the ratchet wheel in response to the movement of the movable plate member from the released position to the attracted position. A detent mechanism for assuredly achieving the stepwise rotation of the ratchet wheel is also utilized and is generally employed in the form of a leaf spring having one end fixed and the other end engaged to the ratchet wheel.
Although the prior art electromagnetic relay switch assemblies operate satisfactorily and effectively, the purpose for which they are utilized is limited. This is because the leaf spring forming a part of the detent mechanism exerts such a relatively large resiliency as to provide a resistance to the pivotal movement of the movable plate member from the released position towards the attracted position while the return biasing force necessary to bias the movable plate member to the released position acts on the movable plate member.
In order to overcome this resistance, the electromagnetic coil means utilized in the prior art electromagnetic relay switch assemblies must be of such a design that, when it is energized, it can exert a magnetic attractive force sufficient to overcome the sum of the resiliency of the leaf spring and the return biasing force.